output the adjacency matrix

cmd/internal/markov/absorbing.go

@@ -24,6 +24,7 @@ import (
 	"gonum.org/v1/gonum/graph"
 	"gonum.org/v1/gonum/graph/encoding"
 	"gonum.org/v1/gonum/graph/simple"
+	"gonum.org/v1/gonum/mat"
 )
 
 type AbsorbingMarkovChain struct {
@@ -37,12 +38,7 @@ func NewAbsorbingMarkovChain() *AbsorbingMarkovChain {
 func (g *AbsorbingMarkovChain) IsValid() bool {
 	for nodes := g.Nodes(); nodes.Next(); {
 		u := nodes.Node().(*node)
-
-		if g.From(u.ID()).Len() == 0 {
-			continue
-		}
-
-		if g.outWeightSum(u) != 1 {
+		if g.outWeightSum(u) > 1 {
 			return false
 		}
 	}
@@ -63,6 +59,24 @@ func (g *AbsorbingMarkovChain) outWeightSum(u *node) float64 {
 	return sum
 }
 
+func (g *AbsorbingMarkovChain) AdjacencyMatrix() mat.Matrix {
+	adj := simple.NewDirectedMatrix(g.Nodes().Len(), 0, math.NaN(), 0)
+	for edges := g.WeightedEdges(); edges.Next(); {
+		adj.SetWeightedEdge(edges.WeightedEdge())
+	}
+
+	a := mat.DenseCopyOf(adj.Matrix())
+
+	nodes := adj.Nodes()
+	for i := 0; nodes.Next(); i++ {
+		id := nodes.Node().ID()
+		u := g.Node(id).(*node)
+		a.Set(i, i, 1 - g.outWeightSum(u))
+	}
+
+	return a
+}
+
 func (g *AbsorbingMarkovChain) NewEdge(from, to graph.Node) graph.Edge {
 	e := g.WeightedDirectedGraph.NewWeightedEdge(from, to, math.NaN()).(simple.WeightedEdge)
 	return &weightedEdge{WeightedEdge: e}

cmd/root.go

@@ -17,12 +17,14 @@ along with this program. If not, see <http://www.gnu.org/licenses/>.
 package cmd
 
 import (
+	"fmt"
 	"os"
 
 	"scm.dairydemon.net/filifa/dptdist/cmd/internal/markov"
 
 	"github.com/spf13/cobra"
 	"gonum.org/v1/gonum/graph/encoding/dot"
+	"gonum.org/v1/gonum/mat"
 )
 
 var file string
@@ -57,6 +59,10 @@ func parse(cmd *cobra.Command, args []string) {
 	if !graph.IsValid() {
 		panic("not an absorbing Markov chain!")
 	}
+
+	a := graph.AdjacencyMatrix()
+	out := mat.Formatted(a)
+	fmt.Printf("%v\n", out)
 }
 
 // Execute adds all child commands to the root command and sets flags appropriately.